The present invention relates to a process for manufacturing glass fiber optical waveguides having a core and a cladding, with the refractive index of the cladding being lower than the maximum refractive index of the core, in the course of which process a rod-shaped preform is manufactured and drawn into the glass fiber optical waveguide.
From German published patent application DE-AS No. 23 00 013, there is known a process in which particulate (soot-like) core material is produced by way of flame hydrolysis, and thereafter sintered into a glass body. The cladding material is thereafter deposited onto the rod-shaped substrate body by flame hydrolysis, and also sintered.
Accordingly, in this approach the shaping of the rod-shaped substrate body is independent of the chemical manufacture of the particulate core material, but the shaping of the cladding material is effected directly by way of deposition from the chemical reaction onto the substrate body. Since the core material as well as the cladding material are produced by flame hydrolysis in the open atmosphere, there is a danger in this process of causing impurities